The Brood are a race of insectoid, parasitic, extraterrestrial beings. The Brood possess wings, fanged teeth and a stinging tail. They have a hive mentality and mindlessly follow a queen. To reproduce, they must infect other races with their eggs. Despite their resemblance to insects, the Brood have endoskeletons as well as exoskeletons. Also unlike insects, they have fanged jaws instead of mandibles. Their skulls are triangular and flat, with a birthmark (such as the battle axe which is most common in broodlings but are different for each Brood) between their large eyes. Their two front legs are actually long tentacles they can use to manipulate objects. Due to their natural body armor and teeth, the Brood are very dangerous in combat. In addition, they have stingers that can deliver either paralyzing or killing poison.

The parasitic Brood have the ability to impregnate a host (of any lifeform) with an egg, making them somewhat similar to Aliens from the Fox franchise. When the embryo is grown, the host becomes a Brood, and is effectively dead. They use a hive mind to pass memory to their hosts, which also passes an individual's knowledge, given to a broodling, to the hive and back to the queen, meaning newborn brood know what any member of a race knows. Until the embryo gains the host's body the embryo can only gain temporary control of the host, often without the host noticing as the host is unaware when it loses control. If the host possesses any genetic powers, the resultant Brood will inherit them. The persona of the host once the Brood is "born" appears to be extinguished, but in some cases the host's will may be strong enough to survive and coexist with the Brood's. Brood also have the ability to morph into their host's original form and a hybrid form with characteristics of both the host and the Brood body.

The Brood are sadistic creatures that enjoy the suffering they intentionally cause others, especially the terror their infection causes their hosts. They have been compared to "demons". The Brood have a civilization based on the typical communal insect societies, such as those of the bees and ants. The Queens are the absolute rulers, while the "sleazoids" do all the work; despite their evil, they never rebel against their Queens, perhaps due to the latter's telepathic abilities. However, the Queens have no allegiance to each other. They also have developed, or stolen, advanced technology.

Their true planet of origin is unknown. They arrived in the Shi'ar galaxy long ago, and began infesting many worlds, becoming deadly enemies to the Sh'iar. In this galaxy they found certain large space-dwelling creatures that they decided to use as living starships. These include the whale-like Acanti, and the shark-like Starsharks. The Brood use a virus that effectively lobotomizes the creatures, then they use bionics to control them. The Brood hollow out part of the creatures (by eating them) and use the space created to live in, like termites eating a tree. This eventually kills the living ships, requiring them to capture new ones.

One of the Acanti they captured was of unusual size (its rib cage alone was the size of a mountain range.) They used it as their main base, and, when it died and crashed onto a planet, used it as their main city. The corpse was so large, it took centuries just to rot halfway. However, predators from the planet they landed on infested the area of the dead Acanti's brain, so the Brood avoided it.

There are several types of Brood:

Broodlings - brown, nearly the size of a human, and have transparent wings. Broodlings have flexible abdomens that they need to coil most of the time. They have an image on their forehead crest, though no meaning is known from symbol to symbol. These are nicknamed "sleazoids" by Kitty Pryde. Most infected hosts become Broodlings. Broodlings are only created by infecting another host with an embryo.

Firstborn - "pure" Brood, they are born directly from hatched eggs and subservient to their mother, the Empress, only. They are green, black, and red in color, and are roughly the size of a human, but smaller than a queen.

Brood Queens - Looking like the Broodlings but slightly larger than humans the Queens are much rarer and infect hosts for the Brood Hive. Queens fulfill the mental command of an Empress, a unique alien who houses the hive mind. Queens can communicate with their spawn by telepathy, even across interstellar distances.

Empress - The Empress, who houses the Brood's hive mind, is green with minor black and red colors. There is only one Empress at a time, and she is massive.

History

The Brood have encountered the X-Men on several occasions. They have been fought by many other superheroes, as well.

School’s Out / High School Never Ends

When Hannah Connover, a human infected with a Brood queen, is brought out of stasisby the Travelers, she is allowed to transform into a Brood queen. She then infects some homeless New Yorkers with Brood embryos, creating a small brood army. The Travelers use mental control to force them into a van. Hannah, in her hybrid human/queen form, drives the van through the gate of Xavier’s school and the Brood attack. They attempt to implant more Brood embryos into the young mutants at the school, but the seniors that are running the school defeat the Brood with the help of Michael, a recent graduate.

Welcome to Paradise / Hotel California

Over winter break at Academy X, many students spend the holidays at Xavier’s school. While at the mall, a group of mutants is attacked by a Brood that managed to survive the attack on Xavier’s school and spawn others of his race. The young mutants are eventually successful in defeating the alien threat, though Wolverine is implanted by an embryo. The Brood that is born from Wolverine is found to be functionally immortal.